For neady ten years，the Unified Modeling Language(UML)has been the industry standardfor visualizing，specifying，constructing，and documenting the【S1】of a software-intensivesystem．As the【S2】standard modeling language，the UML facilitates communication andreduces confusion among project【S3】．The recent standardization of UML 2．0 has furtherextended the language’s scope and viability．Its inherent expressiveness allows users to【S4】everything from enterprise information systems and distributed Web·-based applications to real-timeembedded systems．The UML is not limited to modeling software．In fact，it is expressive enough to model【S5】systems，such as workflow in the legal system，the structure and behavior. of a patienthealthcare system，software engineering in aircraft combat systems，and the design of hardware．To understand the UML，you need to form. a conceptual model of the language，and this re—quires learning three major elements：the UML's basic building blocks，the rules that dictate howthose building blocks may be put together，and some common mechanisms that apply throughout theUML．

【S1】

A．classes

B．components

C．sequences

D．a(chǎn)rtifacts

D解析：近十年來，統(tǒng)一建模語言(uML)已經(jīng)成為工業(yè)標(biāo)準(zhǔn)，它可用來可視化、規(guī)范化說明、構(gòu)建以及文檔化軟件密集系統(tǒng)中的開發(fā)制品。作為事實(shí)上的工業(yè)標(biāo)準(zhǔn)，UML能夠方便項(xiàng)目相關(guān)人員的溝通并減少理解上的二義問題。uML 2．0標(biāo)準(zhǔn)擴(kuò)寬了該語言的應(yīng)用范圍，它所具有的表達(dá)能力能夠讓用戶對企業(yè)信息系統(tǒng)、分布式Web系統(tǒng)和嵌入式實(shí)時(shí)系統(tǒng)進(jìn)行建模。uML不僅能夠?qū)浖到y(tǒng)進(jìn)行建模，實(shí)際上，它具有足夠的能力去對法律系統(tǒng)中的工作流、病人監(jiān)護(hù)系統(tǒng)中的結(jié)構(gòu)和行為、飛行戰(zhàn)斗系統(tǒng)和硬件系統(tǒng)進(jìn)行建模。為了理解UML，需要具備該語言的概念